Desiccation process.



F. W. LIETZOW & 0. F. FLEISCHER.

naslccmou Paocess. APPLICATION FILED MAY 29 [912.

1,282,093. I Patented Oct. 22, 1918'.

2 SHEETSSHEET I.

F. W. LIETZOW & 0. F. FLEISCHER.

DESICCATION PROCESS. v APPLICATION FILED MAY 29, I912.

2 SHEETS-SHEET 2.

Patented Oct. 22, 1918..

ll-llin ZGSSGSJ UNHED STATES PATENT orr on.

FREDERICK WILLIAM LIE'IZOW AND OSCAR FREDERICK FLEISCHER, OF CHICAGO, ILLINOIS, ASSIGNORS TO MERRELL-SOULE COMPANY, OF SYRACUSE, NEW YORK,

A CORPORATION OF NEW YORK.

DESICCATION PROCESS.

To all whom it may concern:

Be it known that we, FREDERICK WILLIAM Lrnrzow and OSCAR FREDERICK FLEISCHER,

citizens of the United States, and residents of Chicago, in the State of Illinois, have invented certain new and useful Improvements in Desiccation Processes, of which the following-is a specification.

Our present invention relates to processes for the recovery in a form substantially free from moisture of the solids contained or carried in fluid or liquid substances or vehicles, or, viewed from another aspect, to processes for removing fluid, liquid or moisture from substances in order to obtain their valuable contents in the form of concentrates; the apparatus employed by us in the carrying out of the said process forming the subject matter of our co-pending application, Serial No. 679,345, filed February 23, 1912. v

The invention has reference to desiccating moist substances in general; to the desiccation of fluids carrying their solid contents in suspension, more particularly; and has special reference to improved methods for recovering such solids in the form of powder or granules, and this without so altering theirform or structure either mechanically or chemically that they may not be reconverted into substantially their original form upon the addition of Water or other fluid equivalent to that removed by the utilization of our improvements in this art.

The principal objects of our present invention are to provide a process whereby we may efiect the desiccation of substances substantially instantaneously and whereby the I solids may be so rapidly and efficiently recovered that on one hand they do not become cooked or altered by too continuous an application of heat, nor on the other hand are they deposited or precipitated in a moist form owing to an inadequate supply of heat or a supply of desiccating gas of too great relative humidity; and whereby we may most efiiciently efl'ect the recovery of any -des-. iccated particles, not preclpitated at the Specification of Letters Patent.

Patented Oct. 22, 1918.

Application filed may 29, 1912. Serial No. 700,450.

time of desiccation, which may be carried by the gas used in the desiccation process,

the provision of a simplified process of the nature referred to characterized by the em-c ployment of an improved arrangement of fluid-feed and gas feed'in the desiccating apparatus; an improved relative arrangement of atomizer nozzles and gas inlets thereln;

improved means for precipitating the desiccated material; an improved arrangement of ratus or of any of the chambers therein;

improved means for exhausting the gaseous contents of the apparatus without substantial loss of any'solids carried in suspensiontherein; improved means for ind uoing a flow of treatment gas therethrough; and generally to improve, simplify and cheapen the cost of carrying out processes of the character stated and render them more efiicient, together with certain further objects which will hereinafter appear.

Desiccation processes in use at this day, as known to us, are largely objectionable in one or more of the following respects, viz: the roduct, if suiliciently dried to be commercially available is apt to become cooked or overheated to such an extent as to be inferior and consequently of depreciated value, or, if not overheated it is often moist, rendering it likely to become spoiled, as by fermentation rendering it useless for many purposes, by caking rendering it less soluble, or otherwise, aside from the practical difiiculties involved in removing it from the apparatus and handling it after such removal, or if the product be obtained without overheating and without an excess of moisture the pro. duction per machine is so loW that the proc ess cannot be carried out on a commercially profitable scale. On the other hand, the apparatus known to us are objectionable in this that they are, within our experience, unduly cumbersome, expensive to build, complex and consequently difficult and expensive to maintain, and inefiicient both with respect compressed air.

to the quantity of fluid which can be eihciently handled thereby per diem and the losses due to the escape of the product obtained unless means be utilized for the recovery of the otherwise exhausted product which auxiliary means are more expensive in operation than the value of the product saved normally warrants.

l l hile our improved process is applicable for the treatment of many substances ofdiverse natures, too numerous here to men tion, we have found it of special value for the treatment of milk in production of mil powder, and We have therefore, for the purpose of disclosing our invention, illustrated in the accompanying drawings an apparatus adapted for desiccation of milk, wherein Figure 1 is a longitudinal elevational view, partly in vertical section, illustrative of a form of apparatus adapted for carrying out our improved process;

Fig. 2 i a plan View, partly in horizontal section, of details of the construction of the apparatus of Fig. 1;

Fig. 3 is a transverse sectional view taken on the line llL-lll of Fig. 1.

Referring now more particularly to the form of apparatus illustrated in Fig. 1, it will be observed that in the form of con struction here employed bv us, for convenience in erection and for certain other rea= sons to be hereinafter disclosed, we employ a preheating chamber 10, a. desiccating chamber 10 a plurality of settling chambers 10, 10 and 10 which may be contiguous or separated as space may permit, that for introducing the milk or other substance to be treated into the desiccating chamber 10 we provide a fiuid supply header 11 communicating by feed pipes.12--12 with the atomizers which terminate in the nozzles indicated at 14.14l directed toward the center of the chamber 10 and toward the source of treatment gas shortly to be described, the fiuid supply header 11 being supplied by a pipe 22 communicating with a tank 23 or other receptacle for containing the supply of material to be treated, a preheater 24 and a pump 100 being interposed in the pipe line 22 for raising the temperature of the fluid and supplying such fluid to the nozzles 1 1 respectively, the fluid being conveniently vaporized in the present.

form of apparatus by means of a relatively low pressure of less than fifty atmospheres established by the pump 100 instead of by For introducing into the chamber 10 the air or other treating gas employed in the desiccation of the atomized spray coming from the nozzles 14:, we employ a gas supply header 16 preferably disposed centrally in the chamber 10- and communicating with the interior of the casing For the purpose of supplying gas to the apparatus in a state most readily absorptive of moisture, to the end that the desiccation of fluid and recovery of the solid content thereof may be most rapidly performed, the gas is introduced into the supply header 16 from a heater 27, wherein we mount in the chamber 10 a radiator 10%- connected by a pipe 25 to any convenient source'of heat supply (not shown) and provide a fan 105 for drawing air in through the intake 106, and ejecting it into the header 16. The orifice of the intake 107 of the fan and 108 of the casing are preferably oppositely disposed to the end that the highest degree of heat to such air and exhaust 109 of the fan and the inlet 110 of the header 16 are desirably oppositely disposed in order to facilitate the forcing of the air into the header 16. v

It will also be seen on inspecting Figs. 1 and 2 that while we employ a plurality of hopper bottoms as indicated at 35 and 36 for removing the contents of the chambers 10 and 10 we equip each of said chambers I with the trough and conveyor devices indicated at 41*", 42 and 41 42*, respectively, the contents of the chamber 10 being deposited adjacent the doors 111. For interrupting the ilow of exhaust gas through the apparatus and thereby in aid of the recovery of any particles of the treated material carried by such exhaust gas we arrange in the casings 10 and 10 a series of vertical bafie members M, 4:5, 46, 47 and 4:8, communication between the chambers 10 and 10 being established by the header 16, between the chambers 10 and 10 by a pipe 112 and between the chambers 10 and 10 by a pipe 113. As a final means for recovering any fine particles, we surround the chamber 10 with screen walls forming a chamber 10 from which the gas finally escapes to the atmosphere.

In carrying out our improved process by lib means of our improved apparatus above described, it is to be noted that the finely divided fluid supplied to the chamber 10 by means of atomizers 14 is directed to the center of the chamber and is met thereabout by streams of air coming from the orifices J ing such a relatively high last mentioned the'soli atomized fluid are. desiccated and powdered aaeaoce 150 degrees Fahrenheit may be maintained substantially instantaneously upon emission from the orifices of the atomizers 14, and

this without becoming either cooked or overheated, or, on the ot er hand, insuficiently dried and'recovered in a practically useless moist condition. Such portions of the desiccated product thus obtained as are not as a matter of course immediately precipitated by gravity against the rising streams of heated air and deposited forthwith adjacent the orifice of the hopper tend to be directed against the bafie members 44:, 45, a6, 47 and 48, and thereupon to be deposited in either the hopper 36 in the'settling chambers 10?, or jin the settling chamber 10, as above suggested. Such particles still remaining in suspensionare restrained from egress by the interruptermembers covering the walls of the settling chamber 10, an similarly deposited.

Since the casing we employ in our said construction is of ut a single thichess, any

particles of desiccated product which may adhere thereto may be easily shaken 0d by striking the casing with a suitably padded mallet which will also serve to loosen any particles which may have adhered to any of the baflie members, after which the slides,

and trays maybe respectively dumped and opened and any residue of the product accumulated thereby discharged into the hoppers or other suitable receptacles.

In ca g out our process above described we find two things especially expedient; firstly, to introduce the air through the orifices 17 at a sufliciently high temperature in order to desiccate the atomized fluid instantaneously upon its entrance to the casing, and, secondly, to discharge such air as well from the chamber 10 as from the orifices'lZ with suficient velocity to at all times 'maintain motion in the treatment gas in order to avoid any substantial humidification, or saturation of any part of the fluid content of the apparatus, and in order not only to prevent the 'formation of any vaporcharged areas but to prevent the accumulation of excess pressure in the apparatus,

By carrying out our improved process in themanner described, we find that we are enabled to attain a substantially dry'prodnot, that is to say, assuming in the rooms containing the apparatus a relative humidity of 50 by hygrometer test, we have a relative humidity of less than 10 in the chamber 10 so that there is no vapor charged area whateverat any point within the several chambers, and that the fumes as finally expelled from the apparatus are of a relative humidity much less than the atmosphere of such room. This is advantageous from two difierent aspects, first, that of the product, since a dry product is assured, and, second, that of cost of maintenance and operation of the equipment, since the absence of moisture largely prevents sticking of the desiccated material to the sides of the apparatus and to the bafie members, slides and doors, as well as to the air inlets and atomizers. We further find that in the case of milk powder we are enabled to produce a cleaner and better colored product than has heretofore been known tous, manifesting not only the absence of 'oxidized but also the avoidance of caramelized or scorched material; that we are enabled to produce finely granulated and more impalpa le powder than has heretofore been obtained,thus one under normal conditions not likely to cake, and one having no tendency to settle to the bottom of or float upon the surface of the liquid used as a vehicle in preparing it for use, one most quickly soluble in water and therefore one most readily prepared for use, and consequently one the largest field of general utility; and that notwithstanding the fineness of the powder the loss of the solidshas been practically reduced to a negliglble quantity.

- Otheradvantages of our present process will be apparent to those who are skilled in the art to which it pertains.

Having thus described our invention and illustrated its use what we claim as new and desire to secure by Letters Patent is:

1. The method of desiccating fluids consisting in atomizing the fluid, and directing the atomized fluid across a desiccating chamber, introducing heated air into the chamber, adjacent the horizontal center thereof and some distance below the atomized liquid when introduced into the chamber, and directing such heated airlaterally and outwardly in the chamber, permitting the atomized fluid to fall through the rising strata of introduced heated air, collecting dry powder in said chamber below thepoint oi introduction of vair into the chamber and discharging the air and vapor from the chamber at a point above the atomized liquid when introduced into the chamber.

2. The method. of desiccating fluids consisting in atomizing the fluid, and directing the atomizedfluid across a desiccating chamber, introducing heated air intothe chamber, adjacent the horizontal center thereof and some distance below the atomized liquid when introduced into the chamber, and directing such heated air laterally and out- Ward in the chamber, permitting" the atomized iuid to fall through the rising strata of introducecl heated air; collecting dry powder is said chamber below the point of inimduc'tion of air into the chamber and ciischarging the air and vapor from the shamiestimony whereof We have hereunto signed? our names in the presence of the We subscnbed wltnesses.

FBEBERWK WILHADI HETZOW. 0501; FEEDEBEUK FLEISCHEE,

"Witnesses l UL CARBENTER,

NESTMAN. 

